Backlit buttons are presently produced by pressure-forming a plastic material. The button surfaces are painted, screen-printed or otherwise marked with a design or label for indicating the particular function or apparatus associated with the button. The pressure-formed buttons have retained or residual mechanical stresses within the formed part thereof, which stresses subsequently induce fracture in within the button rendering the button inoperable or aesthetically unacceptable. Pressure forming of the screen-printed surfaces also frequently induces ink adherence problems such as for example, the development of pinholes, fractures and peeling, as the ink and underlying substrate are simultaneously stretched. An overlaid or painted symbol is susceptible to wear and erasure, which, obviously is also an undesirable side effect.
A thermoformed or molded button may be painted and subsequently marked with a laser-forming technique, however, the depth of the part is limited and the laser imprinting process may lead to wear of the symbol. The laser process may also be beset with problems of inconsistency and is economically unproven.